1 /*
  2  * Copyright (c) 2018, 2025, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
  8  *
  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
 15  * You should have received a copy of the GNU General Public License version
 16  * 2 along with this work; if not, write to the Free Software Foundation,
 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
 22  *
 23  */
 24 
 25 #include "opto/arraycopynode.hpp"
 26 #include "opto/graphKit.hpp"
 27 #include "opto/idealKit.hpp"
 28 #include "gc/shared/c2/modRefBarrierSetC2.hpp"
 29 
 30 Node* ModRefBarrierSetC2::store_at_resolved(C2Access& access, C2AccessValue& val) const {
 31   DecoratorSet decorators = access.decorators();
 32 
 33   Node* adr = access.addr().node();
 34 
 35   bool is_array = (decorators & IS_ARRAY) != 0;
 36   bool anonymous = (decorators & ON_UNKNOWN_OOP_REF) != 0;
 37   bool in_heap = (decorators & IN_HEAP) != 0;
 38   bool use_precise = is_array || anonymous;
 39   bool tightly_coupled_alloc = (decorators & C2_TIGHTLY_COUPLED_ALLOC) != 0;
 40 
 41   if (!access.is_oop() || tightly_coupled_alloc || (!in_heap && !anonymous)) {
 42     return BarrierSetC2::store_at_resolved(access, val);
 43   }
 44 
 45   assert(access.is_parse_access(), "entry not supported at optimization time");
 46   C2ParseAccess& parse_access = static_cast<C2ParseAccess&>(access);
 47 
 48   Node* store = BarrierSetC2::store_at_resolved(access, val);
 49   post_barrier(parse_access.kit(), access.base(), adr, val.node(), use_precise);
 50 
 51   return store;
 52 }
 53 
 54 Node* ModRefBarrierSetC2::atomic_cmpxchg_val_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
 55                                                          Node* new_val, const Type* value_type) const {
 56   if (!access.is_oop()) {
 57     return BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
 58   }
 59 
 60   Node* result = BarrierSetC2::atomic_cmpxchg_val_at_resolved(access, expected_val, new_val, value_type);
 61 
 62   post_barrier(access.kit(), access.base(), access.addr().node(), new_val, true);
 63 
 64   return result;
 65 }
 66 
 67 Node* ModRefBarrierSetC2::atomic_cmpxchg_bool_at_resolved(C2AtomicParseAccess& access, Node* expected_val,
 68                                                           Node* new_val, const Type* value_type) const {
 69   GraphKit* kit = access.kit();
 70 
 71   if (!access.is_oop()) {
 72     return BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
 73   }
 74 
 75   Node* load_store = BarrierSetC2::atomic_cmpxchg_bool_at_resolved(access, expected_val, new_val, value_type);
 76 
 77   // Emit the post barrier only when the actual store happened. This makes sense
 78   // to check only for LS_cmp_* that can fail to set the value.
 79   // LS_cmp_exchange does not produce any branches by default, so there is no
 80   // boolean result to piggyback on. TODO: When we merge CompareAndSwap with
 81   // CompareAndExchange and move branches here, it would make sense to conditionalize
 82   // post_barriers for LS_cmp_exchange as well.
 83   //
 84   // CAS success path is marked more likely since we anticipate this is a performance
 85   // critical path, while CAS failure path can use the penalty for going through unlikely
 86   // path as backoff. Which is still better than doing a store barrier there.
 87   IdealKit ideal(kit);
 88   ideal.if_then(load_store, BoolTest::ne, ideal.ConI(0), PROB_STATIC_FREQUENT); {
 89     kit->sync_kit(ideal);
 90     post_barrier(kit, access.base(), access.addr().node(), new_val, true);
 91     ideal.sync_kit(kit);
 92   } ideal.end_if();
 93   kit->final_sync(ideal);
 94 
 95   return load_store;
 96 }
 97 
 98 Node* ModRefBarrierSetC2::atomic_xchg_at_resolved(C2AtomicParseAccess& access, Node* new_val, const Type* value_type) const {
 99   Node* result = BarrierSetC2::atomic_xchg_at_resolved(access, new_val, value_type);
100   if (!access.is_oop()) {
101     return result;
102   }
103 
104   post_barrier(access.kit(), access.base(), access.addr().node(), new_val, true);
105 
106   return result;
107 }